Characterization of n-InxAl1-xAs/InyGa1-yAs metamorphic high electron mobility transistors (MHEMTs) on GaAs

Abstract

We report the characterization of the first attempt of an n-In_xAl_1-xAs/In_yGa_1-yAs metamorphic high electron mobility transistor (MHEMT) on GaAs substrate grown via Molecular Beam Epitaxy. We used an Indium graded InGaAs metamorphic buffer layer for strain relaxation. The Hall Effect measurements indicate sheet carrier densities of 5.3x10¹² cm^-2, 4.21x10¹² cm^-2, and 4.25x10¹² cm^-2 with associated mobilities of 1,834 cm²/Vs, 3,328 cm²/Vs, and 3,946 cm²/Vs at room temperature, 77K, and 10K respectively. Photoluminescence confirms the occurrence of the InGaAs channel layer in the sample. We attribute the low mobility to the low indium content of 12% in the InGaAs channel and graded buffer layers.